The Risk Analysis of Parametric Rolling to Semi-Submersible Vessel Sailing at Sea

Abstract

Scholars usually studied parametric rolling of container ship, as its speed was very fast. Semi-submersible vessel didn't have fast speed like container ship, but the special way of floating on/off heavy cargo in long waves could cause the requirement of parametric rolling. Because there was a small semi-submersible fleet size in the world, the problem of parametric rolling was neglected by scholars. This paper studied the methods to prevent semi-submersible vessel generating parametric rolling. During the research, we firstly used case calculation to prove semi-submersible vessel that could also generate parametric rolling like container ships. Secondly, we built semi-submersible vessel motion model and found the key factors that influenced parametric rolling occurring or not. Then the method of variable control parameters was employed, and the different parameters including wavelength, wave height, metacentric height and ship speed were changed to quantitatively calculate their influencing degree and rule. Finally, by the case analyzing, parameters value were gotten.